1. Field of the Invention
The present invention relates to a home network, and more particularly, to a method of searching for a Universal Plug and Play (UPnP) device in a UPnP network.
2. Description of the Related Art
A Universal Plug and Play (UPnP) communication protocol used for communication between devices in a home network is a standard for analyzing a message set by a simple object access protocol (SOAP) form on the basis of Internet protocol (IP) packets and analyzing attributes and control information on a device.
In order for a control point to control a UPnP device that is a controlled device connected to a UPnP network, a discovery operation has to be performed. As illustrated in FIG. 1A, the control point has to search for and discovers a UPnP device connected to the UPnP network by using a device type or a service type of the UPnP device. To do this, the control point uses a multicast-search (M-Search) message.
FIG. 1B illustrates a related art structure of the M-Search message. As illustrated in FIG. 1B, the M-Search message includes a <ST> (search target) header, and a <ST> header value includes information on a search condition.
FIG. 1C illustrates related art search conditions that can be used as the <ST> header value of the M-Search message. Specifically, a header value ssdp:all corresponds to a case of searching for all devices and services, a header value upnp:rootdevice corresponds to a case of searching only for a root device, a header value uuid:device-Universally Unique Identifier (UUID) corresponds to a case of searching for a device having a particular UUID, and header values urn:schemas-upnp-org: device: deviceType: v and urn:schemas-upnp-org:service:serviceType:v correspond to cases of searching for a device and a service having a type defined by the UPnP Forum working committee, respectively.
According to the related art method as described above, a user has to set a type of a device or a type of a service to a search condition to search only for a device corresponding to the search condition, and in order to search for a device having an attribute desired by the user, the user has to acquire and analyze a device description or a service description for the same kind of the device or the same kind of the service.
This may cause inconvenience to the user who wants to search only for a device having a particular attribute in a home network including many UPnP devices, and there is a problem in that a large amount of network traffic occurs.